/* eslint-disable no-empty */
import Vue from 'vue'

/*

*  使用方法

*  将以下代码复制到一个js文件中，然后在入口文件main.js中import引入即可；

*  给elementUI的dialog上加上 v-dialogDrag 指令就可以实现弹窗的全屏和拉伸了。

*  给dialog设置 :close-on-click-modal="false" , 禁止点击遮罩层关闭弹出层

*  如果是form表单，不要将提交等按钮放置el-form-item，以免在上下拉伸时被隐藏

*/

// v-dialogDrag: 弹窗拖拽+水平方向伸缩

Vue.directive('dialogDrag', {

  bind (el, binding, vnode, oldVnode) {
    //   弹框可拉伸最小宽高

    let minWidth = 400

    let minHeight = 300

    //  初始非全屏

    let isFullScreen = false

    //  当前宽高

    let nowWidth = 0

    // eslint-disable-next-line no-unused-vars
    let nowHight = 0

    //  当前顶部高度

    let nowMarginTop = 0

    //  获取弹框头部（这部分可双击全屏）

    const dialogHeaderEl = el.querySelector('.el-dialog__header')

    //  弹窗

    const dragDom = el.querySelector('.el-dialog')

    //  给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；

    dragDom.style.overflow = 'auto'

    //   清除选择头部文字效果

    //   dialogHeaderEl.onselectstart = new Function("return false");

    //   头部加上可拖动cursor

    dialogHeaderEl.style.cursor = 'move'

    //   获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);

    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null)

    let moveDown = (e) => {
      //   鼠标按下，计算当前元素距离可视区的距离

      const disX = e.clientX - dialogHeaderEl.offsetLeft

      const disY = e.clientY - dialogHeaderEl.offsetTop

      //   获取到的值带px 正则匹配替换

      let styL, styT

      //   注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px

      if (sty.left.includes('%')) {
        // eslint-disable-next-line no-useless-escape
        styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100)

        // eslint-disable-next-line no-useless-escape
        styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100)
      } else {
        styL = +sty.left.replace(/\px/g, '')

        styT = +sty.top.replace(/\px/g, '')
      }

      document.onmousemove = function (e) {
        //   通过事件委托，计算移动的距离

        const l = e.clientX - disX

        const t = e.clientY - disY

        //   移动当前元素

        dragDom.style.left = `${l + styL}px`

        dragDom.style.top = `${t + styT}px`

        //  将此时的位置传出去

        //  binding.value({x:e.pageX,y:e.pageY})
      }

      document.onmouseup = function (e) {
        document.onmousemove = null

        document.onmouseup = null
      }
    }

    dialogHeaderEl.onmousedown = moveDown

    //  双击头部全屏效果

    dialogHeaderEl.ondblclick = (e) => {
      if (isFullScreen === false) {
        nowHight = dragDom.clientHeight

        nowWidth = dragDom.clientWidth

        nowMarginTop = dragDom.style.marginTop

        dragDom.style.left = 0

        dragDom.style.top = 0

        dragDom.style.height = '100VH'

        dragDom.style.width = '100VW'

        dragDom.style.marginTop = 0

        isFullScreen = true

        dialogHeaderEl.style.cursor = 'initial'

        dialogHeaderEl.onmousedown = null
      } else {
        dragDom.style.height = 'auto'

        dragDom.style.width = nowWidth + 'px'

        dragDom.style.marginTop = nowMarginTop

        isFullScreen = false

        dialogHeaderEl.style.cursor = 'move'

        dialogHeaderEl.onmousedown = moveDown
      }
    }

    dragDom.onmousemove = function (e) {
      // eslint-disable-next-line no-unused-vars
      let moveE = e

      if (e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10 || dragDom.offsetLeft + 10 > e.clientX) {
        dragDom.style.cursor = 'w-resize'
      } else if (el.scrollTop + e.clientY > dragDom.offsetTop + dragDom.clientHeight - 10) {
        dragDom.style.cursor = 's-resize'
      } else {
        dragDom.style.cursor = 'default'

        dragDom.onmousedown = null
      }

      dragDom.onmousedown = (e) => {
        const clientX = e.clientX

        const clientY = e.clientY

        let elW = dragDom.clientWidth

        let elH = dragDom.clientHeight

        let EloffsetLeft = dragDom.offsetLeft

        let EloffsetTop = dragDom.offsetTop

        dragDom.style.userSelect = 'none'

        let ELscrollTop = el.scrollTop

        //  判断点击的位置是不是为头部

        if (clientX > EloffsetLeft && clientX < EloffsetLeft + elW && clientY > EloffsetTop && clientY < EloffsetTop + 100) {

          //   如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;

        } else {
          document.onmousemove = function (e) {
            e.preventDefault() //   移动时禁用默认事件

            //  左侧鼠标拖拽位置

            if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {
              //   往左拖拽

              if (clientX > e.clientX) {
                dragDom.style.width = elW + (clientX - e.clientX) * 2 + 'px'
              }

              //   往右拖拽

              if (clientX < e.clientX) {
                if (dragDom.clientWidth < minWidth) {

                } else {
                  dragDom.style.width = elW - (e.clientX - clientX) * 2 + 'px'
                }
              }
            }

            //   右侧鼠标拖拽位置

            if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {
              //   往左拖拽

              if (clientX > e.clientX) {
                if (dragDom.clientWidth < minWidth) {

                } else {
                  dragDom.style.width = elW - (clientX - e.clientX) * 2 + 'px'
                }
              }

              //   往右拖拽

              if (clientX < e.clientX) {
                dragDom.style.width = elW + (e.clientX - clientX) * 2 + 'px'
              }
            }

            //   底部鼠标拖拽位置

            if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {
              //   往上拖拽

              if (clientY > e.clientY) {
                if (dragDom.clientHeight < minHeight) {

                } else {
                  dragDom.style.height = elH - (clientY - e.clientY) * 2 + 'px'
                }
              }

              //   往下拖拽

              if (clientY < e.clientY) {
                dragDom.style.height = elH + (e.clientY - clientY) * 2 + 'px'
              }
            }
          }

          //  拉伸结束

          document.onmouseup = function (e) {
            document.onmousemove = null

            document.onmouseup = null
          }
        }
      }
    }
  }

})
